The object of this invention is a device to introduce the upper thread into the eye of the needle of a sewing machine.
It is difficult, especially for older persons, to thread a needle with a necessarily very small eye. For one thing, one has to have a very steady hand and for another thing the end of the thread to be pushed through the eye must be free of frayed fibers. For this tedious work, there have been devices introduced that thread the eye partially by hand using an assisting device, or filly automatically with the touch of a button. Regardless of whether the threading is done by hand or automatically using a suitable device, a very fine hook is always necessary to grasp the thread on the other side of the eye and to form a loop of thread when pulled through the eye. For fine needles, such as those in common use for household sewing machines, the thickness of the hook is approximately 0.2 mm. This results in the smallest forces exerted on the hook bending it, thus rendering the entire device to which the hook is anchored unusable. These forces exerted on the hook can occur if, for example, the sewing needle is slightly bent and the eye is not in the prescribed position as a result so that the hook tilting into it hits the needle. For this reason, most known threading devices have guide clips or plates to the side of the hook with conically diverging ends.
An example of this can be found in U.S. Pat. No. 2,538,395. The interior sides of the guide clips, i.e. the two surfaces opposite one another, extend parallel to one another and have a separation that is slightly larger than the thickness of the needle. This means that for each needle size, the right size guide clips must be provided. For a thicker needle, it would not be possible for it to be placed in between the guide clips, and for a thinner needle, it would not be centered and thus the hook would be bent. In order to counteract the bending of the hook and to guide a slightly bent needle in between the two guide clips, the threader is hung elastically. The elastic support protects the hook, butxe2x80x94as already mentioned abovexe2x80x94not against bending when a non-centered thin needle is grasped.
From U.S. Pat. No. 5,615,629, another fully automatic threading device is known whereby the two guide clips are produced from an elastic sheet material and whose interior sides run parallel to one another. The ends of the two guide clips can be deflected outward and thus enable a centering with respect to the needle. Most fine hooks are, however, not protected against bending by this known device since the needle cannot be exactly centered in the middle between the two guide clips when, as shown explicitly in an example of U.S. Pat. No. 5,615,629 in FIG. 6, one clip deviates, thus no longer guaranteeing that it will meet the eye of the needle lying in the middle.
The object of this invention is to create a device to introduce the upper thread into the eye of the needle, wherein the hook always lies exactly in the middle between the two guide clips regardless of the position of the needle and regardless of its thickness.
This object is met by a device with guide clips that include two first sections that are parallel to one another and two second sections that converge together at an angle and are adjacent to the first sections. The second sections transition into curved fourth sections whose peaks have a smaller distance from one another than the adjacent first sections. The curved fourth sections are followed by diverging fifth sections. Advantageous embodiments of this invention are further described below.
The similar design of the two guide clips located to the side of the hook, as well as their symmetric suspension makes it possible to always hold the hook located between them exactly at the same distance from the two interior sides of the clips and thus to introduce it into the eye of the needle without contact. Furthermore, the tilting suspension of the plate carrying the guide clips enables an essentially frictionless centering of the two guide clips with respect to the axis of the needle and thus with respect to the eye of the needle. A bent needle will tilt the plate until the guide clips lie symmetric to the needle. The separation of the guide clips at its narrowest point is smaller than the diameter of the thinnest needle. This makes it possible to acceptably center onto the eye of the needle.